Finally, and this is perhaps the most important point, the Founders Edition cards will not be a limited quantity offer; they will be available at launch and throughout the lifespan of the new Pascal cards. Nvidia also plans to sell the cards directly via its website. So despite the name sounding like something you'd only get if you joined a Kickstarter early on, these will actually be long-term commitments. And that changes the playing field quite a bit. It also explains the higher than MSRP pricing.
There's more to this than just making an alternative card, however. Nvidia has other partners, system vendors, who use their GPUs. Many of these will qualify specific hardware to work in their systems, and some of these vendors really like the old reference cards. They use blowers in place of open air coolers, which means they often work better in SLI configurations or small chassis—Falcon Northwest for example told me they won't put a non-blower GPU in their compact Tiki, due to heat concerns.
If the reference design is only available for a short time before transitioning all graphics card production to the AIB partners, it can make things more difficult for system integrators. Now they can qualify the Founders Edition and rest easy knowing the cards will be available for purchase for a year or more.
And that's basically the whole story:
the Founders Edition will be an Nvidia manufactured card, just like the old "reference" models, only it will continue to be manufactured and sold throughout the life of the GTX 1080/1070 cards. It will carry a price premium, but that appears to be mostly a case of avoiding too much direct competition with their AIB partners.
http://www.pcgamer.com/what-exactly-is-nvidias-gtx-1080-founders-edition